Bridging or spanning of bodies of water

ABSTRACT

A means of spanning rivers and other stretches of water is provided in which a buoyant pipe or tube assembly is employed and anchored down to the river bed. By making use of large tubes fabricated in sections and individually of a diameter sufficient to contain a motor vehicle roadway or railroad, a tunnel type road/rail link may be achieved without cutting into the river bed.

T nit ed States Patent [191 Grant et al.

BRIDGING OR SPANNING OF BODIES OF WATER Inventors: Alan Barnett Grant, Coulsdon,

Surrey; Ralph Sherman, Esher, both 7 of England Alan Grant & Partners, Cabham, Surrey, England Filed: Feb. 10, 1971 Appl. No.: 114,319

Assignee:

US. Cl. 61/43 Int. Cl. Elllg l/00 Field of Search 61/42, 43, 44, 45, 61/72.3, 46, 46.5; 114/206, 209, 230, 231, 121

References Cited UNITED STATES PATENTS 11/1969 Petrik 61/43 9/1885 Case 61/42 8/1907 Smith... 61/43 10/1909 Moir 61/43 Primary Examiner-Dennis L. Taylor Attorney--Rose & Edell 57 ABSTRACT A means of spanning rivers and other stretches of water is provided in which a buoyant pipe or tube assembly is employed and anchored down to the river bed. By

making use of large tubes fabricated in sections and individually of a diameter sufficient to contain a motor vehicle roadway or railroad, a tunnel type road/rail link may be achieved without cutting into the river bed.

2 Claims, 11 Drawing Figures FIG] Inventors ALAN BARE'I'T 683M? 5. RALPH SHERMAN gm F W, Allomc'ys PATENIEflmzm 3.738.112

wmunrs FIG ' Inventors ALAN BRRNE'P'I' GRANT a RALPH SHERHHN a M Allorneyf Inventors ALAN BAR/VE GRANT E; RRLPH SHERMfl/ Q 'rM Attorneys 1 BRIDGING OR SPANNING OF BODIES OF WATER This invention relates to the bridging or spanning of bodies of water, e.g. rivers, estuaries, lakes, straits and, in suitable cases, the open sea, to form road and rail links; or for the conveyance of fluid mediums, such as gas, oil or sewage, in pipelines.

Whereas the conventional means for crossing bodies of water is by a bridge or tunnel, there are many instances where neither a bridge nor a tunnel is a reasonable proposition. The water may be too deep for bridge foundations and/or the distance to be spanned too great for a bridge. It may be impracticable to provide a bored tunnel below very deep water and the ground may be too hard for either a bored tunnel or an excavated trench for an immersed tube tunnel. It is therefore an object of this invention to provide a novel means of spanning stretches of water, particularly for situations where a normal bridge or tunnel is considered impracticable.

According to the present invention, at least one submerged tube or pipe is employed which is buoyantly suspended at a predetermineddepth in the water above the ground or bed, being maintained at its selected position and depth by anchorage means extending down to the bed.

The buoyancy may be provided by the tube or pipe itself or by auxiliary buoyancy means, such as another air-filled tube, secured to it. The anchorage means may comprise cables or rods extending down to anchorages in the ground or bed, or to heavy sinkers, e.g. substantial concrete blocks, resting on the bed.

In the case of a road or rail link, it is convenient to employ at least two large diameter submerged tubes, one for each direction of traffic. Such an assembly of large diameter tubes will ordinarily be excessively buoyant so it is preferred to bind the tubes into a unitary assembly by means of a large mass of reinforced concrete which counteracts the excessive buoyancy and gives a structure of great beam strength.

Various arrangements in accordance with the invention will now be described by way of example with reference to the accompanying drawings, in which:

FIG. 1 is a diagrammatic'cross section through a submerged pipe illustrating the basic concept according to the invention,

FIGS. 2 to 6 show, diagrammatically, modifications or developments of the basic concept,

FIG. 7 is a cross section through a scheme according to the invention for a submerged road/rail link,

FIG. 8 is a diagrammatic side elevation of the scheme of FIG. 7,

FIG. 9 illustrates diagrammatically in cross section a further scheme for a road or rail link,

FIG. 10 shows a modification of the arrangement of FIG. 9, and

FIG. 11 shows an alternative arrangement to .that illustrated in FIG. 8.

FIG. 1 shows a simple arrangement comprising a submerged buoyant pipe II, for conveying gas or sewage for example, maintained at a predetermined position and depth by pairs of divergent anchor cables 12 that extend down to the ground or bed 13 from attachment points at substantially diametrically-opposed points on opposite sides of the pipe.

In FIG. 2, the arrangement of FIG. 1 is modified by the replacement of the pairs of cables 12 by inverted single-cable slings 14. FIGS. 3 shows an even simpler arrangement, in which single nominally vertical cables 15 are employed for anchorage instead of divergent twin cables. Such single-cable anchorages will suffice where there is no significant water movement or where a certain degree of lateral swinging of the pipe can be tolerated. FIG. 4 shows the single cables 15 anchored into concrete sinker blocks 16 resting on the bed 13, instead of into the bed itself.

In FIG. 5 the arrangement of FIG. 1 with twin divergent anchorage cables is shown, but in this case the pipe 1 1 is intended to convey oil or other liquid running substantially full bore so the pipe itself does not possess the buoyancy needed. Separate air buoyancy chambers 17, or alternatively a second continuous air-filled pipe, and therefore attached by cables 18 to the top of the main pipe 11 to act as floats.

In FIG. 6, which again shows single anchorage cables 15, the added buoyancy means is provided coaxially around the pipe 11 in the form of expanded sealed-cell foam plastic sleeves 19. Other forms of providing buoyancy can be used, including a continuous second pipe around and concentric with the liquid-carrying pipe, the annulus between the pipes being filled with air, or a series of separate buoyancy chambers concentric with the liquid-carrying pipe. Instead of being outside the pipe, the expanded foam plastic could be inside the liquid-carrying pipe in the form of a continuous annulus fitting closely inside the liquid-carrying pipe; or it could be of any other convenient cross section such as cylindrical or D- or crescent-shape.

Turning now to FIG. 7, this illustrates the same inventive principle applied to an assembly of tunnel tubes intended to serve as a road-rail like. There are three large diameter tunnel tubes 20, 21 of which the center tube 20 contains the railway while the two flanking tubes 21 carry road traffic in opposite directions. The tunnel tubes 20, 21 are constructed in sections of reinforced concrete or cast iron fabricated on shore and inter-connected by steelwork 22, 23, with the addition of mass concrete 24 to counteract the excessive buoyancy of the tunnels and unite the whole into an integral composite beam of great strength.

This composite ferro-concrete beam is anchored at intervals to the ground or bed by means of sets of four cables or sea-chains 25, 26 secured to anchorage points 27, 28 on the sides and underneath of the two flanking tunnel tubes 21. Each set of anchorage cables comprises an outer divergent pair 25 secured to the outer side of the flanking tunnels and an inner crossed pair 26 secured to the underneaths of the flanking tunnels and leading to the same ground anchorages 29 as the outer pair of cables 25, the whole arrangement being designed to hold the tunnel structure against both lateral and upward movement and tilting. FIG. 8 shows the tunnel with its anchorage cables in side elevation, and illustrates how the tunnel can be maintained at a uniform depth over an uneven bed simply by appropriate selection of the anchorage cable lengths.

If required, fairings 30 can be employed at the sides of the tunnel beam structure to minimize side forces due to water movement. As regards buoyancy, the aim will be largely to balance the upward and downward forces although there must naturally be sufficient buoyancy to ensure that the tunnel displays no tendency to sink under any conditions of current and loading.

Provision may be made for detecting and replacing any anchorage cable that becomes faulty. Each cable can have a length adjustment device 31 and a load cell 32 built into it and it should be possible for at least one cable to be entirely removed for replacement without endangering the structure. Arrangements may be made for continuous monitoring of the individual cable tensions. In construction and maintenance of the tunnel it will be of substantial benefit to provide a track along the tunnel beam top along which an underwater inspection and maintenance vehicle will run and give support for drivers.

As an alternative to the anchorage cable arrangement shown in FIG. 8, it is possible to arrange the anchorage cables in the manner of an inverted suspension bridge, with intermediate shortened cable sets 33 connected to catenary cables 34, as shown in FIG. 11.

In the case of a tunnel which is designed to have passages for ventilation and services placed each side of the tunnel carrying traffic, it may be advantageous to pass the anchor cables or rods through the walls of the ventilation passages. FIG. 9 shows a tunnel beam with a traffic tunnel 41 of rectangular cross section and side passages 42 for ventilation etc. The main anchor cables or rods 43 are connected at 44 to extension cables or rods 45 which pass through watertight glands 46 to anchorages 47 within the passages 42 on the outsides of the walls of the main tunnel 41. Each extension cable or rod 45 includes a length-adjusting device 48, such as a turnbuckle.

Elements 45, 46, 47 and 48 of the arrangement would be assembled before the tunnel is lowered into position, and elements 44 and 45 joined under water, after which the water would be pumped from passages 41 and 42. This would enable final adjustment of anchor lengths to be carried out in air in the passages 42.

In the case of a tunnel placed on, or just above, the sea or river bed, a different arrangement for the anchors can be used. FIG. shows a tunnel beam similar to that of FIG. 9, but with vertical anchor belts 50 passing through vertical holes 51 of circular cross section provided through the walls between the main tunnel 41 and the side passages 42, which walls are thickened locally for this purpose. The anchor bolts have their upper ends secured at the top of the tunnel beam by steel plates 52 and nuts 53, while their lower ends are received in concrete 54 contained within steel anchor tubes 55.

In construction, the complete length of tunnel would be ballasted and sunk into position and connected to the length of tunnel already in place. From a drilling platform on the surface of the water, a drill would be passed through the hole 51 and a hole drilled in the bed. The drill would be withdrawn and a steel tube 55 inserted and driven into place. The anchor bolt would then be positioned and the concrete poured. After the concrete had been allowed to age, the plate 52 and nut 53 would be assembled, and the nuts then adjusted to line up the tunnel. This arrangement allows adjustments to be made in both horizontal and vertical directions. If the tunnel is not far above the bed, the anchor bolts will be capable of resisting side pressure, if any, on the tunnel.

Many modifications and refinements of the arrangements described are, of course, possible without departing from the inventive principle. For instance, the fabrication, assembly and water-tight jointing of the tunnel sections can be accomplished by a variety of techniques.

In addition to allowing water crossings to be effected where no economical alternative exists, the invention also provides a novel means of buoyant tunnel construction which is speedy since it allows the work to proceed at several locations simultaneously, and which makes for ease of fabrication and assembly, the tunnel sections being made on-shore and the work on the bed being, in large measure, carried out from the water surface.

What we claim is:

l. A submerged tunnel construction for spanning a body of water, comprising a plurality of tubes disposed side by side and secured to one another in a unitary assembly, the tube assembly possessing positive buoyancy and being buoyantly suspended at a selected path where it is totally submerged but is above the bed covered by said body of water, anchorage means secured to said assembly to maintain said assembly at said selected depth against the up-thrust of the water acting thereon and against the side thrust of lateral water movements, said anchorage means including a series of pairs of elongated tensile members with the members of each pair extending downwardly in divergent manner to a pair of fixed anchoring stations on said bed, and a mass of dense material united to said tube assembly to counteract, in part only, the buoyancy of said tube; wherein, in addition to the aforesaid pair of tensile members, each pair of anchoring stations has a further pair of elongated tensile members extending upward therefrom and crossing one another before reaching points of attachment thereof to opposite sides of said tube assembly, thereby to provide restraint against tilting.

2. A submerged tunnel construction for spanning a body of water, comprising a tube assembly, the tube assembly possessing positive buoyancy and being buoyantly suspended at a selected depth where it is totally submerged but is above the bed covered by said body of water, and anchorage means secured to said assembly to maintain said assembly at said selected depth against the up-thrust of the water acting thereon and against the side thrust of lateral water movements, said anchorage means including a series of pairs of elongated tensile members with the members of each pair extending downwardly in divergent manner to a pair of fixed anchoring stations on said bed, and further including in addition to the aforesaid pair of tensile members, a further pair of elongated tensile members extending upward from said anchoring stations and crossing one another before reaching points of attachment thereof to opposite sides of said tube assembly, thereby to provide restraint against tilting. 

1. A submerged tunnel construction for spanning a body of water, comprising a plurality of tubes disposeD side by side and secured to one another in a unitary assembly, the tube assembly possessing positive buoyancy and being buoyantly suspended at a selected path where it is totally submerged but is above the bed covered by said body of water, anchorage means secured to said assembly to maintain said assembly at said selected depth against the up-thrust of the water acting thereon and against the side thrust of lateral water movements, said anchorage means including a series of pairs of elongated tensile members with the members of each pair extending downwardly in divergent manner to a pair of fixed anchoring stations on said bed, and a mass of dense material united to said tube assembly to counteract, in part only, the buoyancy of said tube; wherein, in addition to the aforesaid pair of tensile members, each pair of anchoring stations has a further pair of elongated tensile members extending upward therefrom and crossing one another before reaching points of attachment thereof to opposite sides of said tube assembly, thereby to provide restraint against tilting.
 2. A submerged tunnel construction for spanning a body of water, comprising a tube assembly, the tube assembly possessing positive buoyancy and being buoyantly suspended at a selected depth where it is totally submerged but is above the bed covered by said body of water, and anchorage means secured to said assembly to maintain said assembly at said selected depth against the up-thrust of the water acting thereon and against the side thrust of lateral water movements, said anchorage means including a series of pairs of elongated tensile members with the members of each pair extending downwardly in divergent manner to a pair of fixed anchoring stations on said bed, and further including in addition to the aforesaid pair of tensile members, a further pair of elongated tensile members extending upward from said anchoring stations and crossing one another before reaching points of attachment thereof to opposite sides of said tube assembly, thereby to provide restraint against tilting. 